The present invention is directed to systems for controlling water circulation between a container and an external system and, more particularly, to devices for removing and transferring water from the container to the external system, and returning water from the external system to the container so as to maintain a desired water level in the container.
Overflow/water level control systems are typically used for controlling the circulation of water through, as well as the level of water in, a container, such as an aquarium, to which water is added continuously or periodically. In general, means are provided for continually removing water from the container, routing the removed water to an external filter assembly, and then returning the filtered water to the container, while regulating the rates of water removal and return as a means of controlling water level in the container.
Traditionally, this has been achieved by using a hanging-type skimmer box assembly whereby water is skimmed from the surface of the body of water in the container. The basic structure of a skimmer box assembly typically includes an inlet tank, a siphon tube, and an outlet tank, normally with the inlet tank attached to the outlet tank with some means. The skimmer box assembly is mounted on the frame of the container, with the inlet tank partly immersed in the body of water within the container.
In the case of an aquarium, water is pumped into the aquarium from a filtration system located below or behind the aquarium. The water level in the aquarium rises and water from the aquarium flows into the inlet tank. The water level in the inlet tank rises, creating a differential pressure between the inlet tank and outlet tank and forcing water through the siphon tube into the outlet tank on the outside of the aquarium. The outlet tank typically has some means of maintaining a selected water level combined with a means for draining water out of the outlet tank and into the filtration system.
Systems of the type described above usually prove to be quite inflexible. For example, the hang-on tanks or similar devices often prevent placement of the aquarium close to walls. As such, installation of the entire aquarium system is not a simple matter of choice, but is hampered by physical limitations. In addition, users generally find the hang-on devices to be objectionable in appearance, as well as difficult to service. Moreover, depending on the size of the tank, traditional overflow/water level control systems can be quite large. As such, they obstruct a considerable portion of the inner space of the aquarium. Therefore, water circulation and water level control systems are needed that address these shortcomings.